added some examples

Yap/Yapper/components/__tests__/ThemedText-test.tsx

@@ -0,0 +1,10 @@
+import * as React from 'react';
+import renderer from 'react-test-renderer';
+
+import { ThemedText } from '../ThemedText';
+
+it(`renders correctly`, () => {
+  const tree = renderer.create(<ThemedText>Snapshot test!</ThemedText>).toJSON();
+
+  expect(tree).toMatchSnapshot();
+});